Electric lamp for semindirect lighting purposes



April 1937- Q E. T. CAMENISCH 2,078,054

ELECTRIC LAMP FOR SEMIINDIRECT LIGHTING PURPOSES Filed Jan. 6, 1936 5 Sheets-Sheet 1 April 20, 1937.

E. T. CAMENISCH' ELECTRIC LAMP FOR SEMIINDIRECT LIGHTING PURPOSES Filed Jan. 6, 1956 3 Sheets-Sheet 2 April 20, 1937. E. T. CAMENISCH 2,078,054

ELECTRIC LAMP FOR SEMIINDIRECT LIGHTING PURPOSES 5 Sheets-Sheet 3 Filed Jan. 6, 1936 Patented Apr. 29, 1937 star PATENT FFlE ELECTRIC LAMP FOR SEMIINDIRECT LIGHTING PURPOSES Application January 6, 1936, Serial No. 57,729

It) Claims.

My invention consists of an improved electric lamp for semi-indirect lighting purposes, by which all of the advantages of such lamps heretofore used, are retained, and further advantages are secured. Electric lamps of the kind referred to, have been used as both fioor and table lamps, and have commonly been provided with translucent reflectors opening upward and containing relatively high-wattage bulbs for indirect lighting by the light directed upward, and for more subdued lighting around the lamps, by the difiused light projected from the bulbs through the reflectors. In some cases, the lighting around the lamps, has been increased by the use of relatively low-wattage bulbs around the head of the lamp outside of the reflectors, in, for example, cluster sockets. By my invention I employ a translucent reflector, a relatively-high-wattage bulb, and one or more relatively-low-wattage bulbs, but in a manner preventing glare from any and all of said bulbs, by differently constructing the lamp head and reflector as follows: first, all of the lampbulbs employed, are mounted within the refi'ector, and placed to most effectively accomplish the lighting for which each bulb is used; second, the reflector is given a novel conformation to contain the lamp bulbs and efficiently effect the desired lighting from each of the bulbs employed; third, the lamp head is given a novel construction providing an improved mounting for the sockets employed, which at the same time adds to the reflected illumination, and which provides a removable metal closure for the wiring compartment in the head, the lamp head further providing a separable wiring compartment of large size making the connecting of the sockets and switches a simple matter, and providing ample room for all connecting wires so that the danger of injuring the connecting wiring, is eliminated. In addition, my lamp head and reflector are of pleasing appearance, being unmarred by the presence of bulbs or sockets outside of the reflector, and my construction readily meets all requirements of the I. E. S. specifications for semiindirect electric lamps, as to glare and light distribution in different directions around the lamps.

My invention will be best understood by reference to the accompanying drawings illustrating a preferred embodiment thereof, in which Fig. 1 shows the lamp head with the reflector in place thereon, in front elevation;

Fig. 2 is a vertical central, sectional view of the parts shown in Fig. 1, this view being taken along 5 the line 2-2 in Fig. 3, and

Fig. 3 is a plan view of the parts shown in Fig. 1.

Similar numerals refer to similar parts throughout the several views.

As shown in Fig. 2, my improved lamp construc- 5 tion consists of a lamp head Ill comprising upper and lower portions Illa and lob held together by cooperating screw threads N30. The portions Mia and lb are preferably made of white metal by the slush method of casting, to provide any desired external ornamentation and at the same time to leave said portions hollow to provide a compartment ll in the head to contain the connecting wiring, the screw threads lllc being preferably formed in casting the portions I Ea and IN). The lower portion lllb is connected at its lower end in any desired manner, for example, by screw threads 12a, with the upper end of a column or spindle l2 extending to the base of the lamp, not shown, it being understood that my improved construction shown and described, is adapted for use with both floor lamps and table lamps.

The upper end of the head portion its is enclosed by a circular, horizontal, metal plate l3 attached to said head portion by screws 14 as shown in Fig. 3, which plate and the head portions Illa and i027, completely enclose the wiring compartment H with metal walls, thus meeting all requirements of the fire underwriters concerning electrical connection boxes. 30

The plate l3 as shown in Fig. 2, supports a central lamp socket l5 above it, to hold a central lamp bulb i6 constituting the principal source of light for the semi-indirect illumination, which lamp bulb may be of either the single filament type or the double filament type as desired, and the socket l5 may be of the mogul type adapted to the lamp bulb used, or the socket and bulb may be of other types. if preferred. For effective general lighting, it is preferable that the lamp bulb shall be of the double filament type having either and 100 watt filaments, or 100 and 200 watt filaments, depending upon the amount of illumination required. The socket l5 and lamp bulb iii are preferably co-axial with the head Ill.

The plate l3 as shown in Figs. 2 and 3, also supports above it, side sockets I! and IE! to hold additional lamp bulbs l9 and 20 respectively, which sockets preferably have their axes oblique to the plane of the plate I3 and inclined in diiferent directions from each other, the lamp bulbs l9 and 20 being as close to the central lamp bulb It, as safe operation will permit. The purpose of the lamp bulbs 19 and 20 is to furnish either subdued illumination, or to add to the general illumination effected by the central bulb It, as desired, and. I therefore prefer to use lamp bulbs of from 25 to 60 watts and of the single filament type for the lamp bulbs IQ and 2! and sockets of the Edison type to support said lamp bulbs, although other types of lamp bulbs and sockets may be used, if desired.

The plate It is surrounded by a flange led extending upward from and integral with the head portion Illa, and spaced sufficiently from the edge of the plate I3 to form a seat on the upper surface of said head portion and within said flange, for the lower end of a reflector 2!, to support the weight of said reflector. The head portion um is provided with a plurality of equally-spaced ears lile extending upward from the flange lild adjacent the outer surface of the lower end portion of the reflector 21, to carry thumb screws 22 threaded through said ears and cooperating with an outwardly extending bead Zia on the lower end of the reflector, to prevent removal of said reflector from the head portion Illa unless said thumb screws are turned to release said bead.

The reflector 2! is made preferably of translucent vitreous material, for example, white diffusing glass or its optical equivalent. The lower end portion Bib of said reflector, is cylindrical and of such diameter that its inner surface will clear the sockets l1 and I8 in mounting and removing the reflector, and that its outer surface shall have as small a clearance as possible practically, from the inner surfaces of the ears we.

Above the portion 2 lb, and at substantially the filament level of the lamp bulbs l9 and 20, the reflector 2i is curved outward and upward as shown at Zlc, so that this part of the inner surface of the reflector, reflects upward and through the open upper end of the reflector, most of the rays that are directed both downward and outward from all of the lamp bulbs. Above the portion Zlc, the reflector 2| is substantially cylindrical at 2|d, and flares outward but slightly until the level of the top portion of the central bulb i6 is reached, from which point the outward flare of the reflector is more pronounced as shown at 2 is, until the upper end of the reflector is reached, which is well above the top of the central bulb l6, meeting the requirements of the Illuminating Engineering Society specifications as to glare.

In addition to the rays reflected as referred to, a considerable quantity of rays from the lamp bulbs, strikes the reflecting surface of the portion Zic at angles of incidence too great to be reflected di ectly through the upper end of the reflector, which rays by reflection at the portion Zlc, strike the reflecting surface of the portion Zld, and by secondary reflection are directed upward and through the upper end of the reflector. Again, a large part of the rays directed laterally from the central bulb it, strikes the reflecting surfaces of the portions 2m and tie and are thereby reflected through the upper end of the reflector. In this manner, by far the greater part of the rays striking the reflector M, are reflected upward through its upper end, supplementing for indirect lighting purposes, the rays projected from the bulbs upward and without reflection through the upper end of the reflector, leaving but a small part of the rays, particularly from the central bulb it, that is transmitted through and diffused by the reflector 2!, for subdued lighting effect around the lamp, thus meeting the requirements of the Illuminat ing Engineers Society specifications concerning the intensity of light distribution around th lamp.

In addition to all of the rays referred to from the bulbs, another group of rays is projected downward from the bulbs and against the upper surface of the plate it which I prefer to make a reflecting surface, either by polishing said surface, or by coating it with any suitable material having a reflecting surface. As a result, the upper surface of the plate I 3, reflects the rays last mentioned, upward and through the upper end of the reflector 2 5, directly as to some of said rays, and by secondary reflection by the reflector 2! as to others of said rays, thereby supplementing the indirect lighting effect by a considerable quantity of rays that would be lost, were it not for the reflecting surface on the plate i3.

The lamp bulbs described are controlled as shown, by switches 23, and 24 mounted on the head portions ltd and lilb respectively, each of said switches preferably being of a type well known in the art, and adapted to close either or both of two electric circuits, and to open both of said circuits, as described. One of said switches, for example, the switch 23, may control the lighting of the filaments of the bulb l6, and the other of said switches, for example, the switch 2 5, may control the lighting of the bulbs l9 and 20. plate l3 removed from the head portion liia, and With the head portions Ilia and i6!) separated from each other at the screw threads Illc, the wiring 25 can be conveniently connected with the sockets l5, H and 8, with the switches 23 and 24, and with the two-conductor supply cord 26, in the proper manner to control the lighting of the bulbs it, is and 29 as desired, the cord 26 extending through the column or spindle l2 and, when the lamp is in use, being connected with a suitable source of current. When the connections described have been made, the head portions lea and 1% are screwed together, the screw threads ltc having preferably a large and quick lead and being short, for example, about one-quarter of a turn being required to tightly engage said portions with each other, which avoids undue twisting of the connecting wiring 25 in so doing, and the plate 53 is secured in place on the head portion lilac as shown. This forms I a connection box containing said connecting wiring 25, which is completely enclosed by metal walls, the space H in said box being sufficiently large to contain said wiring 25 without squeezing or kinking the same, or in any way injuring its insulation.

The reflector 2! may be surrounded by any desired type of shade supported in any manner, not shown, that is known to the art, if preferred; inasmuch, however, as there are no lamp bulbs outside of the reflector 2i, and the degree of subdued lighting around the lamp may be controlled by the degree of translucency of said reflector, the lamp may be used with satisfactory results without a shade.

By my invention, I thus provide a lamp construction which effectively utilizes the greater part of the light from all of the lamp bulbs for indirect lighting, and which at the same time, utilizes a desired part of said light for subdued and diifused illumination around the lamp; I also provide by said construction, for different amounts of illumination of both kinds, by making it possible to use the central lamp bulb l6 alone, with the several amounts of illumination it af- In wiring the lamp head, with the fords, or by using the 'central bulb I 6 and also either or both of said side bulbs l9 and 20, or by using either or both of said side bulbs I9 and 20 without using said central bulb It. It will be observed, that I am thus able to secure different amounts of illumination that are substantially uniformly distributed around the lamp, and also different amounts of illumination that are not so distributed, but which are principally directed towards the side of the lamp, the latter condition being particularly desirable where the lamp is used near a side wall, or in a corner.

While I have disclosed my invention in the particular embodiment above described, it will be understood that the described construction is illustrative only of my invention, constituting the preferred form thereof, of which, as to any part or parts thereof, I may employ equivalents known to the art at the time of the filing of the present application, without departing from the scope of the appended claims.

Having thus described my invention, what I claim is:

1. In an electric lamp, the combination of a hollow lamp head of metal having an opening at its upper end, a metal plate for closing said opening, devices removably securing said plate to said head, a central lamp socket carried by and above said plate coaxially with said head, a second lamp socket carried by and above said plate at one side of said central socket, electric switches carried by said head for independently controlling current flow to said sockets, and electrical conductors in said head connected with said sockets and said switches, said head having a lower portion for connection with a lamp column and an upper portion for supporting said plate, said head portions having quick lead cooperating screw threads connecting them by which said head portions may be separated from each other or secured together as desired by less than one rotation of said head portions relatively to each other.

2. In an electric lamp, the combination of a hollow lamp head of cast metal diverging upward and outward from its lower end and open at its upper end, a plate removably closing said upper end, electric lamp sockets carried by said plate, and electrical conductors in said head connected with said sockets, said lamp head consisting of upper and lower portions having quick lead cooperating screw threads by which said portions may be joined or separated as desired by less than one rotation of said head portions relatively to each other.

3. In an electric lamp, the combination of a hollow lamp head of metal including upper and lower portions having a joint of substantial internal diameter, said lower portion being adapted to be supported by a hollow column and said upper portion having an openupper end, a metal plate covering the upper end of said upper portion and secured thereto, lamp sockets mounted on and above said plate, said plate having open- 2 ings therethrough for connection wires to said sockets, and switches mounted on said head portions and having connection terminals on the inside thereof, said head portions having quick lead screw threads cooperating to tightly hold them together by less than one rotation of the said head portions relatively to each other, whereby with said head portions separated, said sockets may be mounted in place and electrically connected with said switches and with supply conductors in said column, and said head portions may then be tightly secured together without injury to the connecting wiring.

4. In an electric lamp, the combination of a hollow lamp head of metal including upper and lower portions having a joint of substantial internal diameter, said lower portion being adapted to be supported by a hollow column and said upper portion having an open upper end, a metal plate covering the upper end of said upper portion and secured thereto, lamp sockets mounted on and above said plate, said plate having openings therethrough for connection wires to said sockets, and switches mounted on said head portions and having connection terminals on the inside thereof, said head portions having quick lead screw threads cooperating to tightly hold them together by less than one rotation of the said head portions relatively to each other, whereby with said head portions separated, said sockets may be mounted in place and electrically connected with said switches and with supply conductors in said column, and said head portions may then be tightly secured together without injury to the connecting wiring, said metal plate being otherwise imperforate and having a light-reflecting upper surface.

5. In an electric lamp, the combination of a hollow lamp head of cast metal diverging upward and outward from its lower end and open at its upper end, a plate removably closing said upper end, electric lamp sockets carried by said plate, and electrical conductors in said head connected with said sockets, said lamp head consisting of upper and lower portions having quick lead cooperating screw threads by which said portions may be joined or separated as desired by less than one rotation of said head portions relatively to each other, said plate having perforations for said socket conductors and being otherwise imperforate and having a light-reflecting upper surface.

6. A hollow head for electric lamps including in combination, upper and lower portions for supporting an electric lamp socket and for connection with a support respectively and having cooperating quick lead screw threads connecting them, to contain electrical connecting conductors, whereby with said head portions separated from each other said electrical connections may be made and said head portions may be secured together by less than one rotation of relative movement of said head portions and without injury to said connecting conductors.

'7. A hollow head for electric lamps including in combination, upper and lower cast metal portions for supporting an electric lamp socket and for connection with a support respectively and having cooperating quick lead screw threads connecting them, to contain electrical connecting conductors, whereby with said head portions separated from each other said electrical connections may be made and said head portions may be secured together by less than one rotation of relative movement of said head portions and without injury to said connecting conductors, and a metal plate closing the upper end of said upper portion and constituting the support for said socket.

8. A hollow head for electric lamps including in combination, upper and lower slush cast portions for supporting an electric lamp socket and for connection with a support respectively and having cooperating mold-formed quick lead screw threads connecting them, to contain electrical connecting conductors, whereby with said head portions separated from each other said electrical connections may be made and said head portions may be secured together by less than one rotation of relative movement of said head portions and without injury to said connecting conductors. Y

9. A hollow head for electric lamps including in combination, upper and lower slush cast portions for supporting an electric lamp socket and for connection with a support respectively and having cooperating mold-formed quick lead screw threads connecting them, to contain electrical connecting conductors, whereby With said head portions separated from each other said elec trical connections may be made and said head portions may be secured together by less than one rotation of relative movement of said head portions and without injury to said connecting conductors, and a metal plate closing the upper end of said upper portion and having a lightreflecting upper surface.

10. A hollow head for electric lamps including in combination, upper and lower cast metal portions for supporting an electric lamp socket and for connection With a support respectively and having cooperating quick lead screw threads connecting them, to contain electrical connecting conductors, whereby with said head portions separated from each other said electrical connections may be made and said head portions may be secured together by less than one rotation of relative movement of said head portions and without injury to said connecting conductors, a metal plate closing the upper enclof said upper portion and constituting the support for said socket, said plate having a light-reflecting upper surface, and separable fastening devices securing said plate to said upper portion.

EDWARD T. CAMENISCH. 

